IthaID: 1505
Names and Sequences
| Functionality: | Globin gene causative mutation | Pathogenicity: | N/A |
|---|---|---|---|
| Common Name: | South East Asian (SEA) deletion | HGVS Name: | NC_000011.10:g.5201647_5229059del |
| Hb Name: | N/A | Protein Info: | N/A |
Also known as: Vietnamese, SE Asian, HPFH-7, SEA-HPFH, 27 kb deletion
Comments: The deletion comprises the entire β-globin gene with a total deletion length of 27 kb, resulting of a non-homologous recombination event. In the first time reported as Vietnamese HPFH deletion with approximate size of 30 kb [PMID 7689901]. The 5′ breakpoint is located ~3.5 kb downstream of the δ-globin gene, while the 3' breakpoint is located ~2.3 kb downstream from the 3′ HS-1 site (γ-silencing element) of the β-globin gene. Recent studies determined the exact breakpoints of the deletion and patients haematological indices (microcytosis and increased Hb A2) indicated that the SEA deletion is more akin to a β-thal phenotype with raised HbF, because of the deletion of γ-silencing element.
We follow the HGVS sequence variant nomenclature and IUPAC standards.
Phenotype
| Hemoglobinopathy Group: | Thalassaemia |
|---|---|
| Hemoglobinopathy Subgroup: | β-thalassaemia |
| Allele Phenotype: | N/A |
| Associated Phenotypes: | Hb F levels [HP:0011904] [OMIM:141749] |
Location
| Chromosome: | 11 |
|---|---|
| Locus: | NG_000007.3 |
| Locus Location: | 68557 |
| Size: | 27.412 kb |
| Deletion involves: | β |
Other details
| Type of Mutation: | Deletion |
|---|---|
| Ethnic Origin: | Vietnamese, Cambodian, Chinese Zhuang |
| Molecular mechanism: | N/A |
| Inheritance: | Recessive |
| DNA Breakpoint Determined: | Yes |
In silico pathogenicity prediction
Publications / Origin
- Motum PI, Hamilton TJ, Lindeman R, Le H, Trent RJ, Molecular characterisation of Vietnamese HPFH., Human mutation, 2(3), 179-84, 1993
- Dimovski AJ, Divoky V, Adekile AD, Baysal E, Wilson JB, Prior JF, Raven JL, Huisman TH, A novel deletion of approximately 27 kb including the beta-globin gene and the locus control region 3'HS-1 regulatory sequence: beta zero-thalassemia or hereditary persistence of fetal hemoglobin?, Blood, 83(3), 822-7, 1994
- Xu XM, Li ZQ, Liu ZY, Zhong XL, Zhao YZ, Mo QH, Molecular characterization and PCR detection of a deletional HPFH: application to rapid prenatal diagnosis for compound heterozygotes of this defect with beta-thalassemia in a Chinese family., Am. J. Hematol., 65(3), 183-8, 2000
- So CC, So AC, Chan AY, Tsang ST, Ma ES, Chan LC, Detection and characterisation of beta-globin gene cluster deletions in Chinese using multiplex ligation-dependent probe amplification., J Clin Pathol, 62(12), 1107-11, 2009
- Cai WJ, Li J, Xie XM, Li DZ, Screening for common β-globin gene cluster deletions in Chinese individuals with increased hemoglobin F., Int J Lab Hematol, 37(6), 752-7, 2015
- He S, Wei Y, Lin L, Chen Q, Yi S, Zuo Y, Wei H, Zheng C, Chen B, Qiu X, The prevalence and molecular characterization of (δβ)(0) -thalassemia and hereditary persistence of fetal hemoglobin in the Chinese Zhuang population., J. Clin. Lab. Anal. , 2017